DE102015106988A1 - Zeolites in paints or adhesives for thermoplastic foam injection molding - Google Patents

Abstract

The present invention relates to a coating composition for coating and / or bonding one or more thermoplastic foam moldings comprising at least one adhesive or paint and a molecular sieve, wherein the molecular sieve is suitable for receiving blowing agent, in particular nitrogen and / or carbon dioxide, from the foam molding, and a zeolitic material or a carbon molecular sieve (CMS), as well as a method for producing a coated foam molding, a plastic component with a coated foam molding, and the use of a coating agent.

Description

The present invention relates to a coating composition for coating and / or bonding one or more thermoplastic foam moldings comprising at least one adhesive or lacquer and a molecular sieve, and to a process for producing a coated foam molding, a plastic component with a coated foam molding, and the use of the coating composition.

Technical area

In the meantime, plastics account for between 15 and 20 percent by weight and are increasing in automotive engineering. These are often exterior and interior parts, the latter having their corresponding visual, haptic and functional properties by gluing injection molded components with different surface decorations. In particular, plastic parts are used as injection molded articles for the interior of automobiles, for example instrument panels, door trim or center consoles. These can be glued or painted with both a decor and a plastic part.

In addition, competition in the automotive industry has led to an increasingly wide range of applications for plastics in the direction of lightweight construction, whereby physical foaming, ie the replacement of plastic material by a gas (nitrogen, CO ₂ ), or chemical foaming is also increasingly being used. When physical foaming by MuCell ^® or similar methods nitrogen, carbon dioxide or chemical blowing agent in a supercritical state during plasticizing, for example, injected under pressure into the plastic melt and homogeneously distributed. After injection into the pressureless form, the gas separates again from the melt and forms a fine-celled foam structure. The lack of emphasis and reduced viscosity, minimization or elimination of sink marks and distortion are the key aspects that reinforce the trend.

State of the art

Foamed polymeric articles are known in the art and have many uses. Foams are e.g. used for damping, insulation, weight reduction, impact absorption and thermal, chemical and electrical inertness. Thermoplastic polymer foams can be made using foamed beads or conventional polymer processing techniques such as extrusion, injection molding, reactive injection and mechanical mixing. Foam extrusion typically involves melting the polymer in an extruder, adding a gas or compound which is in a gaseous state at extrusion temperature and pressure, or a source of a gas, e.g. a chemical compound which generates a gas by decomposition, and then extruding the molten thermoplastic polymer through a mold to form a foamed structure. Frequently nucleating agents are also added to the molten polymer so that the pore size and the homogeneity of the resulting foam are improved.

Processes for the production of foamed polymer articles have been described, for example in US 5,726,214 . US 4,877,815 and US 3,072,583 disclosed. JP 08-12796 discloses the use of a combination of boron nitride and a zeolite as a nucleating agent in a composition for foaming fluoropolymer resins.

In the DE 602 19 054 It has been found that zeolites alone can be used without the addition of a gas or a chemical foaming agent to foam a thermoplastic, melt-processable fluoropolymer.

A disadvantage of the prior art processes and moldings is that undesirable outgassing behavior of the moldings occurs during or after the production of foams, which in particular delays the production of laminated or painted components and thus makes them more expensive and less practical. During the early application of a lamination or a lacquer outgassing leads to a disadvantageous blistering, so far had to be waited undesirably long for a fading of the outgassing until a lamination or a coating could be applied to the molding.

Description of the invention

The object of the present invention is therefore to provide means and methods with which the outgassing is reduced or suppressed in such a way that the foam molding can be provided with a lamination or coating as immediately as possible after its production, without causing blistering due to outgassing comes.

This object is achieved by a coating composition for coating and / or bonding of one or more thermoplastic foam moldings having the features of claim 1 and a method for producing a coated foam molding according to claim 8, a plastic component with a coated foam molding according to claim 11 and Use of the coating composition according to claim 12 solved.

The coating composition according to the invention comprises at least one adhesive or lacquer and a molecular sieve, wherein the molecular sieve is suitable for the adsorptive absorption of excess blowing agent, in particular excess blowing agent, in particular of nitrogen and / or carbon dioxide, from the foam molding, and of a zeolitic material or carbon molecular sieve (carbon molecular sieve, CMS).

According to the invention, the outgassing of a shaped body after a foaming process with the aid of the coating agent, which contains at least one adhesive or lacquer and a molecular sieve, is significantly reduced or suppressed. In this case, for example, a zeolite as a molecular sieve excess, outgassing blowing agent or foaming agent, in particular nitrogen and / or carbon dioxide, on.

Another molecular sieve material used in the invention, for example, in commercially available nitrogen gas generators, is the so-called molecular sieve carbon, a particulate carbon material. Various methods have been developed for producing such a particulate molecular sieve carbon. In one method, a phenolic or furan series resin raw material is adsorbed on the surfaces of a porous carbon adsorbent and then polymerized and / or condensed. Subsequently, a carbonization is carried out to form a fine-porous structure in the adsorbent ( JP-OS 49-37036 ). In another method, a hydrocarbon that provides carbon by thermal decomposition is added to coke which is subsequently heat treated to deposit carbon in the fine pores of the coke ( JP-OS 52-18675 ). In yet another method, an organic material that is tacky at room temperature is mixed with fine particles of charcoal and then granulated and carbonated ( Japanese Laid-Open Publication No. 57-175715 ).

Preferably, the at least one adhesive is a 2K dispersion adhesive or a hot melt adhesive containing in each case a polyol component and a hardener component and in an amount of from 90 to 99.999% by weight and the molecular sieve to 0.001 to 10% by weight in the adhesive.

Alternatively, preferably, the at least one paint is a primer or a topcoat, preferably with a polyol component and a hardener component, and in an amount of 90 to 99.999 wt .-% and the molecular sieve to 0.001 to 10 wt .-% in the paint.

In this mass distribution on the one hand, a maximum gas absorption is ensured, on the other hand, the molecular sieve is contained in a sufficiently small amount, without affecting the mechanical properties of an adhesive or paint. In addition, the zeolite in these amounts may assume the property of a filler, but this is not required in the context of the invention.

Preferably, the molecular sieve zeolite material has a pore opening diameter in the range of 0.3 to 0.5 nm, preferably determined according to DIN 66134 and or DIN 66135 , on, and the particles of the zeolitic material have a size in the range of 0.1 to 20 microns. As a molecular sieve, for example zeolite Na-A were experimentally (SYLOSIV A4 ^®, pore size 0.4 nm), zeolite ZSM-5 (silicalite, pore size 0.5 nm) or zeolite A 4 (Zeopor ^® K80, clinoptilolite, pore size 0.4 nm ) used.

However, the pore size of the fine pores of a nitrogen and / or carbon dioxide adsorbing molecular sieve should be controlled within a range of 0.35 nm to 0.5 nm. As a particularly efficient molecular sieve zeolite Na-A have in experiments (SYLOSIV A4 ^®, pore size 0.4 nm), zeolite ZSM-5 (silicalite, pore size 0.5 nm) or zeolite A 4 (Zeopor ^® K80, clinoptilolite, pore size 0 , 4 nm).

Thus, the pore opening diameter of the zeolitic material is preferably in the range of 0.37 to 0.43 nm.

In experiments it was possible to show that the particles of the zeolitic material preferably have a size in the range of 4 to 6 μm, determined according to ISO 13320 , to show a good CO ₂ - or N ₂ -Emissionsaufnahme.

Preferably, the adhesive or paint contains 0.05 to 5.00 wt .-% of the zeolitic material. More preferably, the adhesive or paint contains 0.05 to 1.00 wt .-% of the zeolitic material. The amount used depends on the desired degree of foaming of the foam molding to be coated.

Preferably, the thermoplastic material of the foam molding to be coated is selected from the group consisting of acrylonitrile-butadiene-styrene (ABS), styrene-acrylonitrile (SAN), polystyrene (PS), polycarbonate (PC), polyethylene (PE), polypropylene (PP) , Polyamides (PA), or mixtures thereof. In this case, the thermoplastic foam molding may be fiber-reinforced or unreinforced.

• a) Bereitstellung des Beschichtungsmittels durch Vermischen mindestens eines Klebstoffs oder Lackes mit einem Molekularsieb, wobei das Molekularsieb zur Aufnahme von Treibmittel, insbesondere von Stickstoff und/oder Kohlendioxid, aus dem Schaumformkörper geeignet ist, und aus einem zeolithischen Material oder einem Kohlenstoffmolekularsieb (carbon molecular sieve, CMS) besteht;
• b) Aufschmelzen des thermoplastischen Kunststoffs und Zuführen von Stickstoff (N₂) und/oder Kohlendioxid (CO₂) unter Druck;
• c) Extrudieren der homogenisierten Schmelze oder Spritzgießen in ein Spritzgusswerkzeug; d) Abkühlen;
• e) Auftragen des Beschichtungsmittels, insbesondere enthaltend einen Lack, auf den in d) erhaltenen Schaumformkörper, oder
• f) Auftragen des Beschichtungsmittels auf den in d) erhaltenen Schaumformkörper und Verkleben des Schaumformkörpers mit einem weiteren Bauteil während oder unmittelbar nach dem Abkühlen des Schaumformkörpers, und/oder
• g) Auftragen des Beschichtungsmittels auf den in d) erhaltenen Schaumformkörper und Aufbringen einer Dekorschicht auf den Schaumformkörper während oder unmittelbar nach dem Abkühlen des Schaumformkörpers.

The inventive method for producing a coated foam molding by applying at least one coating agent to the foam molding, which includes a foamed thermoplastic resin which is selected from a group consisting of acrylonitrile-butadiene-styrene (ABS), styrene-acrylonitrile (SAN), polystyrene (PS), polycarbonate (PC), polyethylene (PE), polypropylene (PP), polyamides (PA), or mixtures thereof, comprises the following steps:

• a) providing the coating composition by mixing at least one adhesive or paint with a molecular sieve, wherein the molecular sieve for receiving propellant, in particular of nitrogen and / or carbon dioxide, from the foam molding is suitable, and from a zeolitic material or a carbon molecular sieve (carbon molecular sieve , CMS);
• b) melting the thermoplastic material and supplying nitrogen (N ₂ ) and / or carbon dioxide (CO ₂ ) under pressure;
• c) extruding the homogenized melt or injection molding into an injection mold; d) cooling;
• e) applying the coating composition, in particular containing a lacquer, on the foam molding obtained in d), or
• f) applying the coating composition to the foam molding obtained in d) and bonding the foam molding with another component during or immediately after cooling of the foam molding, and / or
• g) applying the coating composition to the foam molding obtained in d) and applying a decorative layer to the foam molding during or immediately after cooling of the foam molding.

The time interval between steps d) and e) or f) and / or g) is preferably less than 5 h, more preferably less than 1 h. The positive effect of the molecular sieve in the adhesive or varnish is recognizable to the viewer in that after gluing a leather decoration or a film on the injection mold or extruder about 1 to 5 h previously removed foam molded body no foaming or blowing agent bubbles under the leather decor or the Slide become more visible. With the help of the molecular sieve in the adhesive or paint and the corresponding process, the production of laminated components is significantly accelerated and thus cheaper and more practical.

A plastic component according to the invention with a coated foam molding has at least one adhesive or lacquer and a molecular sieve as coating agent, the molecular sieve being suitable for the adsorptive absorption of blowing agent, in particular excess blowing agent, in particular of nitrogen and / or carbon dioxide, from the foam molding, and of a zeolitic one Material or a carbon molecular sieve (CMS) consists.

A coating composition according to the invention is used to manufacture a component, which component is a coated automobile, aircraft or marine accessory or part of a car, aircraft or marine accessory, preferably a coated or laminated interior component.

example

In the following, the invention is explained in more detail by way of example, without wishing to restrict the invention.

1 Figure 5 shows the photograph of a conventional PP injection molded foam molding for the instrument panel of a vehicle, ie without additional molecular sieve, with a transparent decorative film applied about 5 minutes after removal from the injection mold with a conventional dispersion adhesive. Clearly visible is a strong blistering due to the outgassing of N ₂ , which shows up in the dark areas of the recording. The bright areas show good adhesion of the decorative film without blistering. Conducting the experiment with CO ₂ shows the same blistering picture.

It has now surprisingly been found that the bubble formation of the shaped body after the foaming process is significantly reduced or suppressed by a coating of an adhesive or lacquer with a molecular sieve.

2 shows the PP injection molded foam molding for the instrument panel of a vehicle, in which a transparent decorative film was applied approximately 5 minutes after removal from the injection mold in areas with a zeolite-containing adhesive. The bright zeolite-containing areas show no blistering. When performing the experiment with CO ₂ or N ₂ , the suppression of blistering is equally evident. Similarly, the application of a zeolite-containing paint shows the suppression of blistering.

The advantageous effect is based on the adsorptive absorption of the blowing agent or foaming agent, in particular of the excess foaming agent or foaming agent.

In the case of a conventional injection molded article, ie without additional molecular sieve, a decorative layer depending on the plastic used after at least about 44 h after removal (matching) of the molding of the Injection molding tool applied largely free of bubbles. So far, it had undesirably long waited for a decay of the outgassing until a lamination could be applied to the molding.

3 shows by way of example the void structure of Kinopthilolith, a natural, colorless, crystalline aluminosilicate, which in its hydrated form has the empirical formula (Na ₂ K ₂ CaMg) ₄ Al ₈ Si ₂₈ O ₇₂ 27 H ₂ O. While the synthetic zeolite, eg, zeolite A, is a binder-formed powder, the natural zeolite, such as cineapilolith, is a broken rock.

Kinoptilolite has a mean pore size of 0.5 nm, cf. 3 , Although clinoptilolite, main constituent of Zeopor ^® K 80 shows only a low suitability as a drying agent, but is a suitable molecular sieve for the purposes of the invention. A comparable effect experimentally showed the synthetic zeolite A having a pore opening diameter in the range of 0.3 to 0.5 nm.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 5726214 [0005]
• US 4877815 [0005]
• US 3072583 [0005]
• JP 08-12796 [0005]
• DE 60219054 [0006]
• JP 49-37036 [0012]
• JP 52-18675 [0012]
• JP 57-175715 [0012]

Cited non-patent literature

• DIN 66134 [0016]
• DIN 66135 [0016]
• ISO 13320 [0019]

Claims (12)

 Coating agent for coating and / or bonding of one or more thermoplastic foam moldings, which comprises at least one adhesive or paint and a molecular sieve, wherein the molecular sieve for adsorptive absorption of blowing agent, in particular of nitrogen and / or carbon dioxide, from the foam molding is suitable, and from a zeolitic material or a carbon molecular sieve (CMS). A coating composition according to claim 1, wherein said at least one adhesive is a dispersion adhesive or a hot melt adhesive each having a polyol component and a hardener component and contained at 90 to 99.999% by weight and said molecular sieve at 0.001 to 10% by weight. The coating composition according to claim 1, wherein the at least one varnish is a primer or a topcoat, preferably with a polyol component and a hardener component, and is contained at 90 to 99.999% by weight and the molecular sieve at 0.001 to 10% by weight. A coating composition according to any one of claims 1 to 3, wherein the particles of the zeolitic material have a size in the range of 0.1 to 20 μm and the zeolitic material has a pore opening diameter in the range of 0.3 to 0.5 nm.  Coating composition according to claim 4, wherein the particles of the zeolitic material have a size in the range of 4 to 6 μm. A coating composition according to claim 4 or 5, wherein the pore opening diameter of the zeolitic material is in the range of 0.37 to 0.43 nm. Coating composition according to one of claims 1 to 6, wherein the thermoplastic foam molding comprises at least one plastic selected from the group consisting of acrylonitrile-butadiene-styrene (ABS), styrene-acrylonitrile (SAN), polystyrene (PS), polycarbonate (PC ), Polyethylene (PE), polypropylene (PP), polyamides (PA), or mixtures thereof. A process for producing a coated foam molding by applying at least one coating agent to the foam molding which comprises a foamed thermoplastic resin selected from a group consisting of acrylonitrile-butadiene-styrene (ABS), styrene-acrylonitrile (SAN), polystyrene (PS ), Polycarbonate (PC), polyethylene (PE), polypropylene (PP), polyamides (PA), or mixtures thereof, comprising a) providing the coating composition by mixing at least one adhesive or paint with a molecular sieve, wherein the molecular sieve for receiving blowing agent , in particular of nitrogen and / or carbon dioxide, is suitable from the foam molding and consists of a zeolitic material or a carbon molecular sieve (CMS); b) melting the thermoplastic material and supplying nitrogen (N ₂ ) and / or carbon dioxide (CO ₂ ) under pressure; c) extruding the homogenized melt or injection molding into an injection mold; d) cooling; e) application of the coating composition, in particular containing a lacquer, to the foam molding obtained in d) or f) application of the coating composition to the foam molding obtained in d) and bonding of the foam molding with another component during or immediately after cooling of the foam molding, and / or g) applying the coating composition to the foam molding obtained in d) and applying a decorative layer to the foam molding during or immediately after cooling of the foam molding. A method according to claim 8, wherein in step a) the molecular sieve, preferably the zeolitic material, is added to the hardener component. A method according to claim 8 or 9, wherein the time interval between steps d) and e) or f) is less than 5 h, preferably less than 1 h. Plastic component with a coated foam molding, obtainable by a process according to one of claims 8 to 10, wherein the coating agent comprises at least one adhesive or lacquer and a molecular sieve, wherein the molecular sieve for receiving excess blowing agent, in particular nitrogen and / or carbon dioxide, from the foam molding is suitable, and consists of a zeolitic material or a carbon molecular sieve (CMS). Use of a coating agent for coating and / or bonding one or more thermoplastic foam moldings according to any one of claims 1 to 7 for the production of a plastic component according to claim 11, wherein the plastic component is a coated or glued car, aircraft or marine accessory or part of a car, Aircraft or marine accessory, preferably a coated, glued or laminated interior component is.

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